Milking plant and method for reducing sound emissions in a milking plant

ABSTRACT

The invention relates to a milking plant wherein the vibrations and sound emissions thereof are significantly reduced. In said inventive milking plant, a vacuum control valve ( 500 ) is directly connected to a vacuum compensation tank ( 200 ). The vacuum control valve ( 500 ) leads into the vacuum compensation tank ( 200 ) via a diffusor ( 501 ). The vacuum control valve ( 500 ) is enclosed in a cylindrical container ( 503 ). Preferably, the vacuum pump ( 110 ) and the vacuum compensation tank ( 200 ) are connected to each other via a main line ( 150 ) which is embodied in the form of two bent, flexible hoses. Preferably, the main line ( 150 ) leads tangentially into the vacuum compensation tank ( 200 ). The invention also relates to a method for reducing sound emissions in one such milking plant. According to said method, the flow speed of the air in the air-guiding parts ( 150, 200, 300, 302, 403, 420 ) of the milking plant is reduced. A buffer tank ( 300 ) can be used in the air line ( 30 ), enabling a stable operating vacuum to be obtained in addition to a reduction in structure-borne noise.

CROSS REFERENCE TO RELATED APPLICATION

This application is a U.S. national stage of International ApplicationNo. PCT/CH02/00292, filed Jun. 5, 2002 and claiming a priority date ofJun. 7, 2001, and published in a non-English language, and prioritythereto for common subject matter is hereby claimed.

BACKGROUND OF THE INVENTION

The present invention relates to a milking installation and to a methodfor the reduction of noise emissions in a milking installation.

Previously disclosed milking installations consist of numerous componentparts, the interaction of which facilitates the milking of cows, sheepor goats. A vacuum is created by means of a vacuum pump unit, whichcomprises a vacuum pump and its drive motor. This vacuum is applied inan air line, to which the actual milking device is connected. A vacuumequalization tank is generally provided in order to maintain a stablevacuum. The vacuum equalization tank makes a certain volume of airavailable, whereby initial equalization of fluctuations in the vacuumcan take place. Further equalization takes place by means of a vacuumcontrol valve. By opening and closing the vacuum control valve, theadmission of outdoor air into the system is controlled in such a waythat the vacuum is maintained at a stable level.

At least one pulsator is also provided in a milking installation. As arule, the pulsator consists of one or two independent, pneumatically orelectrically directly (armature) or indirectly (membrane) activatedvalves, with the help of which in the milking device itself continuousalternation takes place between low pressure and normal pressure, whichaffects the actual milking procedure. The milking device consists offour teat cups and one collector piece. This is placed on the teats ofthe animal to be milked. The milking device has two connecting hoses.There is thus a pulsation hose, which is connected to the air line viathe pulsator, and via which the milking procedure consisting of asuction phase and a pressure release phase is effected.

The milking device also exhibits a milk hose, by means of which the milkis led away. This discharges either into the milk pail or into a milktransport pipe, the so-called milk pipe. The milk is conveyed via thismilk pipe to an end unit, the so-called milk collection vessel. The milkflows into this vessel and, on reaching a specific level, is led away bymeans of a milk pump to the actual milk storage tank, in which the milkis cooled and stored until collection. Finally, a safety separator isalso provided. This is connected to the milk collection vessel. In theevent of failure of the milk installation control system, the milkcollection vessel may become overfull. The milk then flows into thesafety separator. A float valve is raised here in sequence to close theoutlet and the connection to the vacuum equalization tank. Operation ofthe milking installation is interrupted in this case. The milk in thesafety separator must be drained manually and disposed of.

Milking installations of this kind are a source of constant noise whenthey are in operation. This noise derives from various elements of amilking installation. The elements responsible for generating theprincipal noise and vibrations can be mentioned.

Let us first make reference here to the vacuum pump unit. On the onehand this generates noise, for example in the form of engine noise,which is propagated through the air and which lies in the audible range.However, the noise is also propagated in the air pipe. Finally, becausethe air pipe is attached to the milking framework via flexibleconnections, the entire milking framework is caused to oscillate. Theoscillations can also be transmitted in this way to living beings thatare associated with the milking framework. The noise generated by thevacuum pump unit can also be propagated via the fabric of the buildingin the form of so-called structure-borne noise. This can ultimately leadto the oscillations being distributed through the entire structure ofthe building. A further unpleasant side-effect can also arise as aresult of noise reflections occurring in the vacuum tank and in the airpipes, which contribute to multiplication of the noise frequency. It canalso result in interference phenomena, whereby the amplitudes of thedisturbances are amplified. This could lead to a frequency range beingreached, which corresponds to the natural frequency of the milkingparlour framework and is sufficiently powerful to excite this, too.

The pulsators must be regarded as a further source of disturbance.Pulsators today are electrically operated as a rule. The directlyoperated pulsators exhibit an armature valve, the impact of which in theend position provokes a heavy, jerking impulse. This impulse isconducted in the form of structure-borne noise directly into the airpipe and the milking parlour framework. The impact noise is clearlyperceivable acoustically. Pulsators with indirect valve control arequieter in operation, on the other hand, because a membrane exhibitslittle mass. A particular disadvantage in this respect is the fact thatthe opening and closing movement takes place very rapidly and, in sodoing, forces a powerful air blast into the air pipe, which is similarlycapable of producing a disadvantageous effect. This noise emissionmanifests itself on the one hand via the vacuum, and on the other handas structure-borne noise. Multiplication of the impact intensity canoccur as a consequence of the parallel connection of all the pulsators.A further negative effect is that air enters the air pipe at regularintervals as a consequence of the pulsation. The vacuum is disturbed inthis way, and this can trigger an opposing reaction in the sensitivevacuum control valve.

The vacuum control valve can be mentioned as the third source of noise.The vacuum control valve varies the admission of air so that the vacuumcan be maintained at a constant level. The velocity of the arriving airis dependent on a variety of factors. It is thus dependent on thequality of manufacture of the valve, but also on the location of themilking installation above sea level, and thus on the atmosphericpressure. At an altitude of 1500 m, the velocity of the arriving air caneven reach the speed of sound. As soon as the speed of sound is reached,however, stall conditions occur briefly. This condition is associatedwith a whistling noise. The entry of air into the vacuum system afteropening the control valve is perceived in any case, however, since theair enters the vacuum system relatively rapidly, so that turbulencephenomena and oscillations occur. In addition, the milk pump is also oneof the principal sources of noise.

The generated noises, vibrations and oscillations are distributedthrough the entire milking installation. They are ultimately alsoperceived by the animals, both on the basis of their transmissionthrough the air, and on the basis of structure-borne noise, for examplevia the milking parlour frameworks against which the animals lean duringthe milking procedure. High-output animals are extremely sensitive,however, and react even to the slightest disturbances by giving areduced milk yield. The general well-being of the animals is alsosusceptible to disruption in this way and, in extreme cases, an arrestedmilk flow can lead to udder inflammation.

The current state of the art has until now offered only two approachesto the reduction of these noise and vibration effects. It is known thatthe application of a rubber covering to all pipes, and in particular thepipes constituting the air pipe, reduces the propagation of noise in thepipe. Another approach is revealed in the playing of music, inparticular classical music, in the milking area, which is claimed toproduce an increase in the flow of milk from the animals and to improvetheir psychological state. However, the previously disclosed approachesto finding a solution are ultimately unsatisfactory and insufficient.

Further problems are associated with the vacuum control valve inconventional milking installations. Thus, a consequence of the pressurewave generated by the pulsator is that the sensitive vacuum controlvalve begins to oscillate, in spite of the fact that the vacuum remainsstable from an overall point of view. As a result of this, too much airis supplied to the system as a whole, which must be removed by thevacuum pump. The vacuum can fall significantly as a result of this, infact within a period of ca 1 second. However, the constant operation ofthe vacuum pump causes the vacuum to rise again relatively quickly.Vacuum instability prevails within the system, in spite of this, andthis should be avoided in order to ensure a good milking procedure.

SUMMARY OF THE INVENTION

The purpose of the present invention is thus to make available animproved milking installation compared with the state of the art. Inparticular, a milking installation should be made available with steeplyreduced emissions of vibrations and noise. Moreover, the milkinginstallation that is made available should exhibit improved tolerance tosmall fluctuations in the vacuum. Furthermore, a method for thereduction of noise emissions in milking installations should be madeavailable.

A milking installation in accordance with the invention consists of thefollowing components, which are already described in greater detail inrelation to the state of the art: a vacuum pump unit, a vacuumequalization tank, a main pipe between the vacuum pump and the vacuumequalization tank, a vacuum control valve, an air pipe, at least onepulsator, at least one milking device that is connected via a pulse hoseto the air pipe and via a milk hose to a milk pipe, a milk pipe, a milkcollection vessel and a safety separator. Contrary to the state of theart, however, the vacuum control valve in a milking installation inaccordance with the invention is attached directly to the vacuumequalization tank. Because a state-of-the-art vacuum control valvefrequently generates noises, even as high as whistling tones, as outsideair is admitted, and because the vacuum control valve also reactsextremely sensitively to fluctuations in the vacuum, as described above,the attachment of the vacuum control valve to the vacuum equalizationtank enables the vacuum as a whole to be kept more stable, as any changein the vacuum must occur inside the relatively large volume of thevacuum equalization tank before the vacuum control valve opens. Asalready outlined, however, the fact that the opening of the vacuumcontrol valve and the subsequent admission of air constitute asignificant source of noise in the system is associated with aconsiderable advantage in the form of a steep reduction in noiseemission.

There is also a particular preference for a diffuser to be provided onthe vacuum control valve, by means of which the velocity of the airentering the vacuum equalization tank is reduced to such a great extentthat this noise can be lowered by four to five decibels. The diffuserpreferably exhibits a smooth surface on the inside in order to ensure anunimpaired air flow. Polyester reinforced with woven glass fibre is thepreferred material. It is also preferable for the air supply to thevacuum control valve to be provided externally, or, to put it anotherway, for clean air from the outside area to be supplied when the vacuumcontrol valve is opened, for example via a hose pipe.

A further preferred illustrative embodiment of the invention providesfor the main pipe between the vacuum pump and the vacuum equalizationtank not to assume the form of a rigid pipe, but at least the form of aflexible, curved hose. An effective reduction in the propagation ofstructure-borne noise is already achieved through the use of a hose inplace of the pipe. Provision is also made for a number of hoses, inparticular two hoses, to be routed in parallel, so that the flowvelocity of the air lies below a specific limit for a relatively smalldiameter of the hose. Provision is also made for this hose to dischargetangentially into the vacuum equalization tank; to put it another way,this hose discharges tangentially to the principal direction of flow ofthe air. A circular air flow through the tank is encouraged in this way.The fact that turbulence phenomena are kept low by the provided entryand exit of the air also leads to a reduction in noise emissions. Adividing wall is also provided in the vacuum equalization tank. On theone hand this obliges the circular air flow, and on the other hand thestrong intake noise of the vacuum pump is sealed off from the milkingside. An air filter is incorporated in this dividing wall. Thisdistributes the air flow over the whole area, and the flow is caused toslow down accordingly and is thus quieter.

A further illustrative embodiment provides for the air that is fed fromthe safety separator to the vacuum equalization tank not to bedischarged directly into the vacuum equalization tank, but for adivision of the air to be undertaken. This is effected by the connectionin series of a number of parallel, hose-formed dividing elements. Theseparallel hose-formed dividing elements discharge into the vacuumequalization tank via a dome. Division of the structure-borne noisewithin the vacuum system is achieved in this way. The oscillations athigher frequencies, which are caused by the vacuum control valve, arealso attenuated.

A further preferred illustrative embodiment relates to the one pulsatorat least. This is flexibly attached, for example suspended by means ofrubber hoses, from the fabric of the building (ceiling), from themilking parlour framework or from the air pipe. The propagation of thenoise generated by the pulsator, and in particular the impact noisegenerated by the armature valve, to the air pipe and its spread to themilking parlour framework is prevented, i.e. it is separated bytechnical measures.

A further illustrative embodiment provides for the air pipe to bereplaced by a buffer tank, which is arranged in the immediate vicinityof the pulsator. This buffer tank is connected to the vacuumequalization tank by means of an elastic pipe with a small diameter, inparticular a rubber hose. This also permits transmission on the basis ofstructure-borne noise or propagation of the noise in the vacuum to beprevented. Provision is also made for the volume in the buffer tank tobe about 30 litres per connected pulsator. The diameter of the buffertank should be dimensioned according to its distance from the connectedpulsators, in such a way that the available volume can be allocatedimmediately to the pulsator. In this way, the pressure wave does notreach the vacuum equalization tank and is thus unable to causeregulation of the vacuum control valve.

A particular component is the reduction of the velocity of the airflowing in the air-carrying elements. This reaches far in excess of 20m/s in previously disclosed milking installations; in an installation inaccordance with the invention, it is reduced to less than 8 m/s. Thenoise and vibration emissions are greatly reduced by means of thedescribed measures (individually or in combination). It is possible inthis way to take particular steps to prevent the transmission of thevibrations to the animals by structure-borne noise. The well-being notonly of the animal, but also of the milker, is increased in this way.Animal health is also improved. Ultimately, an improvement in thequality of the milk and a higher milk yield are achieved in this way.Poor output and failure to produce by the animal can also be reduced.

The method in accordance with the invention for the reduction of noiseemissions in a milking installation provides for reduction of the flowvelocity of the air in the air-carrying parts of the milkinginstallation. The emission of noise is reduced significantly in thisway. This can be attributed to two physical causes. On the one hand aslower air flow and the associated slower passage of the air through theelements of the milking installation lead to the avoidance of noiseslargely or even entirely, for example whistling noises, which arecaused, for example, by the air flowing past an edge at high speed. Thereduction in the velocity of the air for a constant frequency of thenoise also leads to the amplitude of the noise being kept lower. Areduction in the sound power has two consequences. On the one hand thedisturbing and frequently encountered frequency band around 200 Hz is nolonger perceived as such by humans and animals, and on the other handthe sound level in the area of the milking parlour is then too low tocause the milking parlour framework to resonate. Slight vibrations of apurely tactile nature can still be felt in the installation, however.

A preferred illustrative example of the method in accordance with theinvention provides for the air from the vacuum equalization tank toenter and exit tangentially to the principal direction of flow. The airis obliged to adopt a certain direction of flow in this way, which leadsto the far-reaching avoidance of turbulence phenomena and the associatedhigh air velocities, which can lead to strong reflections at variouspoints in the tank. It also provides for the air from the vacuum pump tobe supplied from the vacuum equalization tank via a main pipe in theform of two flexible curved hoses. The use of curved hoses leads to themechanical movement (vibration) of the pump device not being able topropagate itself in a linear fashion to the connected vacuumequalization tank. By using a hose with a small internal diameter, theair flow on the internal wall is slowed down, and a significantproportion of the disturbing sound waves from the vacuum pump areabsorbed. The resistance to which the flowing air is subjected resultsin a corresponding drop in pressure in the connecting pipe. The flowvelocity also increases in line with the increasing difference inpressure between the inlet and outlet of a pipe. In order to keep theflow velocity low, an increase in the transport capacity by the use ofat least a second hose connection is necessary.

The method in accordance with the invention preferably also provides forthe supply of air to the vacuum equalization tank via the control valveto take place via a diffuser. The physical principle that applies hereis that the flow velocity of the air is reduced by enlarging thediameter of the passageway through which the air passes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a milking installation previouslydisclosed in the prior art;

FIG. 2 is a top view of a section of a milking installation inaccordance with the invention;

FIG. 3 is a side view of the milking installation shown in FIG. 2;

FIG. 4 is a side view of a further detail of a milking installation inaccordance with the invention; and

FIG. 5 illustrates a preferred suspension arrangement for a pulsator.

DETAILED DESCRIPTION OF THE INVENTION

As can be appreciated from FIG. 1, a milking installation previouslydisclosed in the prior art consists of a number of component parts. Themilking installation in accordance with the invention also exhibitsthese previously disclosed component parts. There is accordingly no needfor them to be explained and described in greater detail here. A milkinginstallation thus exhibits a vacuum pump unit 10, which consists of theactual vacuum pump 11, its drive motor 12 and an outlet 13. The vacuumpump unit 10 stands on a base 14. A vacuum is created in theair-carrying system of the milking installation by the constant pumpingout of air by the vacuum pump 11. A main pipe 15 connects the vacuumpump 11 to a vacuum equalization tank 20. An air pipe 30, which isexecuted as a ring circuit in the execution example in FIG. 1, exitsfrom the vacuum equalization tank 20. The air pipe 30 may also have a“blind” end, however, and a circuit is not essential. An air-carryingpipe 40 also discharges into the vacuum equalization tank 20. On the onehand air from the vacuum control valve 50 is supplied via theair-carrying pipe 40 to the vacuum equalization tank 20 via the feedpipe 41, and on the other hand the safety separator 90 is ventilated orevacuated by means of the pipe 40 via the pipe 42. The relatively largeair volume of the vacuum equalization tank 20 serves to keep the vacuumstable, since small changes in the application of the vacuum can beequalized by this large volume. Fine regulation of the vacuum takesplace by means of the vacuum control valve 50, which opens or closes asrequired and, in so doing, either supplies air from the outside orinterrupts this air supply.

The pulsator 60 is an important part of the milking installation. Itapplies a vacuum to the milking device 70 cyclically. The milking device70 consists of four teat cups 71 and the collector piece 75. It isattached to the pulsator 60 by means of a pulse hose 76, and to the milkpipe 81 by means of the milk hose 77. The pulsator 60 is, eithersecurely attached to the air pipe 30 or is mounted on a transportableelement capable of being clipped to the air pipe 30. The milk aftermilking is led to an end unit, namely a milk collection vessel 80, viathe milk hose 77 and the milk pipe 81. Milk flowing in from the milkingdevice 70 is collected here and is pumped in portions by means of themilk pump 82 into the end collection vessel, the so-called milk tank. Inthe event of the milk collection vessel 80 overflowing due to atechnical fault, a safety separator 90 is provided, into which theexcess milk is taken via a pipe 83 in order to prevent milk finding itsway into the air-carrying system. The quantity of milk held in thesafety separator 90 must not be released for human consumption. Thedirection of flow of the milk in the milk-carrying elements of themilking installation is indicated by the arrows. The basic numbering ofthe individual component parts of the milking installation has beenretained logically in the other Figures and is extended by one digit.

FIGS. 2 and 3 show a top view and a side view of a vacuum pump unit 100in accordance with the invention with a main pipe 150, vacuum controlvalve 500 and vacuum equalization tank 200. In the interests of betterunderstanding, the direction of flow of the air in FIG. 3 is indicatedby arrows. The vacuum pump unit 100 is now mounted on elastic, inparticular rubber feet 141, 142, whereby the transmission of noise tothe floor is reduced. The vacuum pump unit 100 consists of the actualvacuum pump 110 and its drive motor 120, which are arranged on a chassisframe 140. The vacuum pump 110 exhibits on the one hand an exhaust airpipe 113, which discharges into the outlet 130 (not shown here). Thevacuum pump 110 also exhibits a supply pipe 111, which discharges intothe main pipe 150 via the pipe 112. The main pipe 150 is connected tothe supply pipe 112 via an adapter 152. Provision is also made for thisconnection to be articulated, in particular via an adjustable pipethread 153, whereby the position of the main pipe 150 can be varieddepending on the spatial situation. Provision is thus made in accordancewith the invention for the main pipe 150 to consist of a flexible hosematerial, which produces a particularly positive effect-on theprevention of the propagation of airborne and structure-borne noise.

Provision is also made, as can be appreciated from FIG. 2, for two mainpipes 150 a and 150 b to be provided, instead of a single main pipe 150(see FIG. 1, reference designation 15). It is also possible to providemore than two main pipes 150 a and 150 b, for example from three to tenin number. These satisfy the characteristics in accordance with theinvention equally. The air flowing in the direction of the vacuum pump110 is combined together again by means of the adapter 114. By analogywith the two main pipes 150 a, 150 b, two supply pipes 112 a, 112 b and152 a, 152 b are also provided. A further reduction in noise is alsoachieved by this division of the air flow into two main pipes 150 a, 150b. The two main pipes 150 a, 150 b discharge via two matching end pieces151 a, 151 b in the vacuum equalization tank 200.

The invention also provides for the main pipe 150 to dischargetangentially into the vacuum equalization tank 200 to promote a circularflow of air within the vacuum equalization tank. In this way, the airflow arriving from the vacuum equalization tank 200 is not diverted fromits principal direction of flow as it enters the main pipe 150. Thistangential air supply can take place at low angles relative to theprincipal axis A of the vacuum equalization tank 200. Provision is alsopreferably made for the tangential air supply to take place at an angleof 5 to 30°, and in particular 16°, formed by the principal axis A ofthe vacuum equalization tank 200 and the center line 211 of the airsupply. The air flowing into the vacuum equalization tank 200 (e.g.arriving from the air pipe or from a buffer tank 300) flows uniformlythrough the interior 207 of the vacuum equalization tank 200 in agenerally circular direction, as indicated by an arrow. A dividing wall201 provided in the vacuum equalization tank 200 imposes circular andmore favorable guiding of the air. Additional provision is preferablyalso made for the air flow to be guided through a close-meshed filter202. The air flow as it passes is thus distributed more or less over theentire surface of the filter. On the one hand higher frequencies areabsorbed in this way, and on the other hand potentially harmful foreignbodies for the vacuum pump are excluded.

Further noise attenuation is achieved by standing the feet 203, 204 ofthe vacuum equalization tank 200 on resilient members, such as rubberfeet or similar damping materials 205, 206 on the floor. Additionalprovision is preferably also made for the vacuum control valve 500 to beattached directly to the vacuum equalization tank 200. Provision is alsomade for the vacuum control valve 500 to discharge via a diffuser 501into the vacuum equalization tank 200. In this way the air flowing invia the vacuum control valve 500, as indicated by corresponding arrows,is fed into the vacuum equalization tank 200 through the progressivelywidening passage of the diffuser 501. The flow velocity of the suppliedair is thus reduced, which in turn leads to a reduction in the resultingnoises.

Provision is also made for the vacuum control valve 500 to be surroundedby a cylindrical container 503. The container 503 insulates the vacuumcontrol valve 500 acoustically from its surroundings on the one hand,and on the other hand it produces a specific air flow to the vacuumcontrol valve 500. Provision is made in addition for ambient air to besupplied to the vacuum control valve via a hose 502, in conjunction withwhich the hose 502 has its intake orifice preferably in the externalarea of the milking installation, so that a constant supply of freshair, preferably free from dust, is always provided. If the vacuum pumpunit 100 is protected by a noise insulation cover, an additional coolingarrangement will be required. Alternatively, the possibility isavailable to extract the heated air from this cover via the hose 502.The path of the air through the vacuum control valve 500 is indicated bycorresponding arrows.

As an additional access, the vacuum equalization tank 200 is providedwith a chamber or so-called dome 401, into which the pipe 40 and 42arriving from the safety separator 90 discharges. This discharge doesnot take place directly, however, but via an adaptor consisting ofparallel-routed, non-fibrous rubber hoses, as explained and describedbelow with reference to FIG. 4. The individual supply openings 402 tothe dome 401 are indicated in FIG. 2. In the illustrative embodiment inFIG. 2, 13 supplies 403 and 13 associated supply orifices 402 areprovided. Their number may vary depending on the delivery output of thevacuum pump. The surface area is significantly enlarged by thissubdivision into several non-fibrous elastic hoses in relation to asingle hose with the same air flow velocity. The air encounterssignificantly stronger frictional resistance in this way. In conjunctionwith the specific length of this divided section, an effective barrieris obtained for the prevailing noises (frequencies) in the vacuumequalization tank.

A diversion 301 to the buffer tank 300 is also provided (see FIG. 3).This is used to supply air to the vacuum equalization tank 200, and thisair is then supplied via the main pipe 150 a and 150 b to the vacuumpump 110. Provision is preferably made for the buffer tank 300 to beacoustically separated from the vacuum equalization tank 200. This isachieved by the connection in series of a flexible pipe 302, preferablya rubber hose with a small cross section. Any occurring acoustic events,which are introduced into the buffer tank 300 by the pulsator 60, areattenuated in this way. The buffer tank 300 is arranged in the immediatevicinity of the pulsator 60. The volume of the buffer tank 300 isdimensioned in such a way that the pulsating air arriving as a pulsecycle from the pulsator 60 is capable of producing only a tolerable fallin the vacuum in the buffer tank 300. The buffer tank 300 is attachedelastically to the fabric of the building (ceiling) or to the milkingparlour framework. The diameter of the air pipe 302 must be dimensionedin accordance with a specific conductivity, so that the level of thevacuum at the end of a given pulse cycle reverts precisely to the valueprevailing inside the vacuum equalization tank 200. In order to achievethe necessary conductivity, it is preferably possible to connectsections of different length and diameter to one another in the air pipe302.

FIG. 4 shows the air guide in the area of the dome or chamber 401. Thevacuum equalization tank 200 with its feet 203, 204 is only representedschematically. The other inlets and outlets (151, 501 and 301) and thevacuum control valve 500 are not illustrated. The pipe 420 arriving fromthe safety separator 90 now discharges in accordance with the inventionnot directly via the dome 401 into the vacuum equalization tank 200, butis separated from it. For this purpose the air is split in an adapter404 into a variable quantity of hose-formed dividing elements 403. Thehose-formed dividing elements 403 discharge via the opening 402 into thedome 401 and thus into the vacuum equalization tank 200. The number ofhose-formed dividing elements 403 can be selected as required, and inparticular in accordance with the pumping capacity of the vacuum pump110. The number of hose-formed dividing elements 403 provided shouldpreferably be between four and twenty. An acoustic division is providedby the design of this transition in accordance with the invention, or,to put it another way, the separation between the vacuum pump and themilking system; any noise that is present is not passed on, but isabsorbed in the hose-formed dividing elements 403.

A further embodiment of the pulsator 60 in accordance with the inventionis represented in FIG. 5. This is flexibly attached, in particularsuspended by means of rubber hoses 601. In this way, the pulsator 60 isno longer rigidly attached to the air pipe 300, but is suspended bymeans of flexible elements, in particular rubber hoses, whereby theimpact noises generated by the pulsator 60 are damped.

1. A milking installation comprising: a vacuum pump having a suctionside and an exhaust side; a vacuum equalization tank connected to thesuction side of the vacuum pump by a first pipe; at least one pulsatorconnected to the vacuum equalization tank by a second pipe; at least onemilking device attachable to an animal to be milked during use of themilking installation and connected to the at least one pulsator by apulse hose; and a vacuum control valve that is attached to the vacuumequalization tank and that admits ambient air through a diffuser intothe interior of the vacuum equalization tank to control the level ofvacuum in the vacuum equalization tank, the diffuser projecting into theinterior of the vacuum equalization tank and reducing the flow velocityof the admitted ambient air to thereby reduce noise associated with theambient air flow.
 2. A milking installation according to claim 1;wherein the vacuum control valve is enclosed by a cylindrical container.3. A milking installation according to claim 1; further including an airhose having one end open to ambient air and the other end connected tosupply ambient air to the vacuum control valve.
 4. A milkinginstallation according to claim 1; wherein the first pipe comprises twoflexible hoses each connected at one end to the suction side of thevacuum pump and connected at the other end to the vacuum equalizationtank.
 5. A milking installation according to claim 4; wherein the otherends of the two flexible hoses terminate in end pieces that project intothe vacuum equalization tank at an angle effective to promote circularair flow within the vacuum equalization tank.
 6. A milking installationaccording to claim 1; wherein the vacuum equalization tank containstherein a dividing wall that partially divides the interior of thevacuum equalization tank and helps promote circular air flow within thevacuum equalization tank.
 7. A milking installation according to claim6; wherein the vacuum equalization tank contains therein a filterdisposed in the path of the circular air flow.
 8. A milking installationaccording to claim 1; further including a safety separator connected toone end of a third pipe, the other end of the third pipe being connectedto one of the ends of plural hoses, and the other ends of the pluralhoses being connected to and opening into a chamber that opens into thevacuum equalization tank.
 9. A milking installation according to claim8; wherein the plural hoses comprise five to twenty hoses.
 10. A milkinginstallation according to claim 1; wherein the at least one pulsator isflexibly suspended from a support.
 11. A milking installation accordingto claim 1; further including a buffer tank connected between the atleast one pulsator and the vacuum equalization tank by a flexible pipe.12. A milking installation according to claim 1; wherein the vacuumequalization tank is supported on resilient members.
 13. A milkinginstallation according to claim 1; wherein the vacuum equalization tankhas a generally cylindrical shape having a length approximately equal toits diameter.
 14. A milking installation according to claim 1; whereinthe first pipe has one end connected to the suction side of the vacuumpump and the other end terminating in an end piece that projects intothe vacuum equalization tank at an angle effective to promote circularair flow within the vacuum equalization tank.
 15. A milking installationaccording to claim 14; wherein the vacuum equalization tank has agenerally cylindrical shape, and the end piece projects into the vacuumequalization tank at an angle effective to promote circular air flowaround the interior of the cylindrical-shaped vacuum equalization tank.16. A milking installation according to claim 1; wherein the diffuserhas a progressively widening passage in the direction in which thediffuser projects into the vacuum equalization tank.
 17. A milkinginstallation according to claim 1; wherein the first pipe is comprisedof flexible hose material.
 18. A milking installation according to claim1; further including a safety separator connected to the vacuumequalization tank through a plurality of flow-dividing elements, theflow-dividing elements dividing the flow of air from the safetyseparator into a plurality of parallel-routed air flows that dischargeinto the vacuum equalization tank.
 19. A milking installation accordingto claim 18; wherein the flow-dividing elements comprise elastic hoses.20. A milking installation according to claim 18; further including achamber connected to and projecting into the vacuum equalization tank,the flow-dividing elements being connected to discharge theparallel-routed air flows into the chamber from which the air flows intothe vacuum equalization tank.